This invention relates generally to an air regulator valve for a ventilated cage and rack system and, in particular, to an air regulator valve for maintaining the balance of exhaust air pressure provided to a plurality of racks connected to a room ventilation system when a rack or racks are disconnected.
Ventilated cage and rack systems are well known in the art. One such ventilated cage and rack system is disclosed in U.S. Pat. No. 4,989,545, assigned to Lab Products, Inc., in which an open rack system including a plurality of shelves, each formed as an air plenum is provided. Air ventilation is provided directly to animals within each cage by allowing air to travel within each shelf to a plurality of predetermined positions within the rack. Exhaust ventilation is provided to the racks by a room exhaust ventilation system. Generally, a facility exhaust ventilation system is capable of supporting a plurality of racks and includes a common exhaust blower unit to maintain the exhaust air pressure to all the racks.
A drawback of connecting multiple racks to a facility exhaust ventilation system, in the manner done in the prior art, is that when one rack is either connected or disconnected from the facility exhaust system, the pressure drop of the room exhaust system is changed and as a result the balance of exhaust air pressure to the remaining racks is adversely affected. Therefore it is desirable to provide a system in which the balance of exhaust air pressure provided to the remaining racks is not affected each time racks are disconnected from the facility exhaust system.